What do light-emitting squid have to do with your gut? Unless you lunched on some really exotic calamari, I’m talking about symbiotic animal-bacteria relationships.

Researchers at UW-Madison are taking advantage of the symbiotic relationship between the Hawaiian bobtail squid and a luminescent bacteria, Vibrio fischeri, as a model for beneficial microbe-host interactions like those that help us digest our food and regulate our immune systems. Humans host thousands of bacterial species, the vast majority of which are innocuous or even beneficial. Only a handful pose a threat. So what sets a platonic relationship apart from a pathogenic one?

A new paper out this week in the Proceedings of the National Academy of Sciences suggests the answer lies not with the bacteria, but with the host itself. Researchers identify a slew of microbe-induced genetic changes in the tiny squid, including a set of evolutionarily conserved genes that may hold the secrets to developing a mutually beneficial relationship.

The results – including the involvement of several genes typically associated with responses to bacterial infection – suggest we may need to rethink our understanding of the main purpose of the immune system, according to the lead scientist. Perhaps the common signaling pathways we think of as “anti-pathogen” pathways actually evolved as symbiosis pathways.

Take a moment to appreciate your resident microbe community, and read the full story.

When the world’s most powerful particle accelerator starts up later this year, exotic new particles may offer a glimpse of the existence and shapes of extra dimensions.

Researchers from the University of Wisconsin-Madison and the University of California-Berkeley say that the telltale signatures left by a new class of particles could distinguish between possible shapes of the extra spatial dimensions predicted by string theory.

Much as the shape of a musical instrument determines its sound, the shape of these dimensions determines the properties and behavior of our four-dimensional universe, says Wisconsin physicist Gary Shiu, lead author of a paper in the Jan. 25 issue of Physical Review Letters.

“There are myriad possibilities for the shapes of the extra dimensions out there,” he says. “It would be useful to know a way to distinguish one from another and perhaps use experimental data to narrow down the set of possibilities.”

Such experimental evidence could appear in data from a new particle accelerator, the Large Hadron Collider, scheduled to begin operating later this year near Geneva, Switzerland.